National surveillance data indicate that the face of heroin use is getting younger. Currently, little is known about this new, apparently younger, cohort of heroin users and injecting drug users (IDUs), but there is substantial evidence that they commonly engage in HIV-risk activities. Family or parent interventions have been effective in preventing substance use and other types of deviant behavior among youth, so it stands to reason that such programs may be effective for HIV prevention. In addition, many young IDUs still live at home with a parent or guardian and receive some type of support as well. Regardless if their relationships are strained or dysfunctional, there is a need to explore the effects of involving parents in their children?s substance use intervention, including treatment and harm reduction. The purposes of the proposed study are to 1) determine the feasibility of involving parents in a three-session intervention including education and prevention case management, and 2) evaluate the effects of the intervention. 650 parents and their IDU youth (aged 18-25 years) will be recruited in Chicago for the proposed study. The intervention design is (a) three sessions for parents --(1) a group education session on harm reduction, (2) a one-on-one session with a case manager, and (3) a joint session with their IDU offspring and the case manager; and (2) two sessions for young IDU offspring-- (1) a one-on-one session with a case manager, and (2) the joint session with their parents and the case manager. The specific aims of the study are to: (1) Explore parents'/guardians' knowledge and opinions regarding harm reduction (i.e., safe injection and sexual behaviors) as an appropriate response to their children's heroin use, and (2) Assess the willingness of parents/guardians of young IDUs to attend three sessions of harm reduction education and prevention case management, their actual attendance and responses to the sessions, and intervening factors that shape these outcomes, and (3) Measure the effects of the intervention on (a) parents'/guardians' active involvement in their children's heroin use problems and opinions about harm reduction, and on (b) young IDUs help-seeking behaviors. The proposed study will build on two of our studies of young IDUs in Chicago. Results will contribute to the design of effective HIV prevention efforts that involve the parents of young IDUs.